Power Control Algorithm for Hybrid Excavator With Supercapacitor

This paper shows several structures of the hybrid excavator with the supercapacitor and compares them with each other from the aspect of fuel efficiency, the additional cost due to the hybridization, and the expected payback time. According to the comparison result, it can be concluded that a compound-type hybrid structure is a better solution than others because of its short expected payback time and higher reliability. In addition, the power control algorithm of the engine and the supercapacitor is proposed. To verify the proposed algorithm, the computer simulation and the engine dynamo test were performed, and the results are presented. The results show that the proposed control algorithm can achieve balance of the power and the energy between the energy sources and the load, and by hybridization, the fuel consumption can be reduced by about 24% compared with the conventional hydraulic excavator. The hardware implementation is now in progress for a 22-ton class excavator.